*
    margin 0
    padding 0

.header
     height 100px
     background-color green
     h1
      font-weight 700
      font-size 26px
      color blue

.footer
    background pink
    height 100px


main  
    display flex
    nav,div,aside
     height 500px
     width 200px
     background-color yellow
    nav
     background-color grey
    aside
     background-color red
    div
     width calc(100% - 400px)

    
